I'm in the finishing stages of applying to grad schools with applications due on the 15th right now and I just received a rather distressing phone call from my mother, who insists that if my applications aren't already in at this point (she cited 2 weeks early) that the admissions committees will interpret this as grad school not really being important to me. As she was once on the admissions committee at her dental school (international), I am concerned that she is correct. I have been spending time recently trying to refine my statement of purpose as much as possible, but since talking to her I've (understandably, I think) become extremely stressed about trying to send in everything immediately. Is it true that an application sent in a couple of days before the deadline looks bad?

I have served on many cycles of graduate admissions, and I have NEVER considered the submission date as indicative of a student's interest in our program (even late applications are usually given the benefit of the doubt). The exception to this rule may be programs that receive hundreds of applications. If committee members try to get ahead of the process by reading the early submissions early, then submitting early may help. However, a complete application includes both your materials and the letters of recommendation, the latter of which often arrive a few days after the deadline. So, my recommendation would be to continue fine-tuning your application so that you have the best representation of yourself in your submitted materials. Of course, do keep track of the deadlines so that you don't submit late!

I don't think so. Dental schools are different from PhDs and different countries have different conventions. I do not think you should take it seriously. In fact, you can argue the other way. If it's handed in right before the deadline, then it means the student really values the school and tries to edit the SoP as much as possible to make it perfect.

As long as it's submitted before the deadline it's good. In fact, it's pretty common for students at my schools to submit it the day it's due because of finals.

The only exceptions are schools with rolling application process, e.g. UIUC. But that application is not due until January.